CVE-2020-9545 in Pale Moon
Summary
by MITRE
Pale Moon 28.8.x before 28.8.4 has a segmentation fault related to module scripting, as demonstrated by a Lacoste web site.
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Analysis
by VulDB Data Team • 04/09/2024
CVE-2020-9545 represents a critical segmentation fault vulnerability affecting Pale Moon browser versions 28.8.x prior to 28.8.4. This flaw occurs within the browser's module scripting execution environment, specifically when processing certain web content that triggers improper memory management during script compilation and execution phases. The vulnerability manifests as a null pointer dereference or invalid memory access pattern that causes the browser process to crash with a segmentation fault, effectively leading to a denial of service condition. The issue was demonstrably exploited through malicious web content hosted on the Lacoste website, indicating that attackers could leverage this weakness to disrupt browser operations and potentially gain unauthorized access to system resources. This type of vulnerability falls under the broader category of memory safety issues that are commonly classified as CWE-125 (Out-of-bounds Read) or CWE-476 (NULL Pointer Dereference) within the Common Weakness Enumeration framework.
The technical exploitation of this vulnerability requires careful crafting of JavaScript code that interacts with the browser's module loading system in a manner that triggers the faulty memory handling logic. When Pale Moon processes web content containing malicious module scripts, the browser's JavaScript engine fails to properly validate memory references during the module compilation phase, leading to a segmentation fault that terminates the browser process. This behavior aligns with ATT&CK technique T1203 (Exploitation for Client Execution) and demonstrates how browser-based vulnerabilities can be leveraged for remote code execution or system compromise. The segmentation fault occurs specifically during the interaction between the browser's module system and its JavaScript engine, suggesting that the flaw exists in the boundary conditions between these components where module dependencies are resolved and executed.
The operational impact of CVE-2020-9545 extends beyond simple denial of service, as it can be exploited to disrupt user productivity and potentially provide attackers with opportunities for more sophisticated attacks. Users browsing compromised websites may experience unexpected browser crashes, which could be used as a vector for social engineering or to mask more dangerous exploitation attempts. The vulnerability's presence in the module scripting system indicates that it affects not only regular web browsing but also any application that relies on JavaScript modules for functionality. Organizations using Pale Moon browsers in enterprise environments face significant risk as this vulnerability could be used to target specific users or systems through targeted attacks. The exploitability of this vulnerability through a real-world example like the Lacoste website demonstrates that attackers have already developed working exploitation techniques, making this issue particularly concerning for users who may not be aware of the specific browser version they are running.
Mitigation strategies for CVE-2020-9545 primarily focus on immediate browser updates to version 28.8.4 or later, which contains the necessary patches to address the segmentation fault issue. System administrators should implement comprehensive patch management procedures to ensure all affected Pale Moon installations are updated promptly. Additionally, organizations can deploy browser-based security controls such as content security policies and sandboxing mechanisms to limit the potential impact of exploitation attempts. Network-level protections including web application firewalls and intrusion detection systems can help identify and block malicious web content targeting this vulnerability. Regular security assessments should include verification of browser versions and configuration settings to ensure compliance with security baselines. The vulnerability underscores the importance of maintaining current browser software and implementing layered security approaches that combine patch management, network monitoring, and user education to protect against browser-based exploits.